Simultaneous measurements of cations and anions using diffusive gradients in thin films with a ZrO-Chelex mixed binding layer.
Simultaneous measurements of cations and anions using diffusive gradients in thin films with a ZrO-Chelex mixed binding layer.
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DOI：
10.1016/j.aca.2017.04.007
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发表时间：
2017-06
影响因子：
6.2
通讯作者：
Yan Wang;S. Ding;Lei Shi;Mengdan Gong;Shiwei Xu;Chaosheng Zhang
中科院分区：
文献类型：
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作者：
Yan Wang;S. Ding;Lei Shi;Mengdan Gong;Shiwei Xu;Chaosheng Zhang
本文采用改进的ZrO-Chelex结合凝胶，利用薄膜扩散梯度（DGT）技术，建立了同时测量8种阳离子[Fe(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II)]和8种氧离子[P(V)， V(V), Cr(VI), As(III)/As(V), Se(VI), Mo(VI), Sb(V)， W(VI)]的新方法。每种分析物在混合溶液中的结合动力学表明ZrO-Chelex凝胶的快速吸收。与阳离子相比，阴离子表现出较慢的吸收速率，这并不影响DGT的吸收。采用两步萃取法，用1.0 M hno3洗脱阳离子，然后用0.2 M NaOH和0.5 M h2o2混合溶液洗脱阴离子，获得了稳定的阳离子和阴离子洗脱效率。用ZrO-Chelex DGT在混合溶液中同时测量阳离子和阴离子，发现与溶液pH（5-9）和离子强度（2-3 mM至750 mM）无关。ZrO-Chelex DGT在99.5、127.6、301.2、33.3和87.4 μg cm−2下测定了Fe（II）、P(V)、Cd（II）、As（III）和As(V)的单次测量容量。除海水中的Se（VI）外，使用ZrO-Chelex DGT对天然淡水和海水中的所有阳离子和阴离子进行了精确测量。该技术同时测量16种元素的性能也在沉积物中进行了测试。
A new method for the simultaneous measurements of eight cations [Fe(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II)] and eight oxyanions [P(V), V(V), Cr(VI), As(III)/As(V), Se(VI), Mo(VI), Sb(V), and W(VI)] was established in this study using the diffusive gradients in thin films (DGT) technique with an improved ZrO-Chelex binding gel. The binding kinetics of each analyte in a mixed solution indicated a rapid uptake on the ZrO-Chelex gel. The anions exhibited slower absorption rates compared to the cations, which did not affect the DGT uptake. Stable elution efficiencies for these cations and anions were obtained based on a two-step extraction procedure using 1.0 M HNO3for elution of the cations followed by a mixed solution containing 0.2 M NaOH and 0.5 M H2O2for elution of the anions. Simultaneous measurements of the cations and anions with the ZrO-Chelex DGT were validated in mixed solutions and found to be independent of solution pH (5–9) and ionic strength (2–3 mM to 750 mM). The capacities of the ZrO-Chelex DGT for single measurements of Fe(II), P(V), Cd(II), As(III), and As(V) were determined at 99.5, 127.6, 301.2, 33.3, and 87.4 μg cm−2. Except for Se(VI) in seawater, accurate measurements of all of these cations and anions in natural freshwater and seawater were obtained using the ZrO-Chelex DGT. The performance of this technique for simultaneous measurements of 16 elements was also tested in sediments.